Facebook’s Custom Audiences offers a powerful targeting platform that allows you to upload lists of current customers and email subscribers and match them to Facebook profiles for ad targeting. But wait—if you’ve already got their email address, what more could you want from them? Turns out, a lot. With Facebook Custom Audiences you can create lookalike models for additional ad targeting, as well as retarget known users to drive conversions. Here are just a few ways to use Facebook Custom Audiences to generate opt-in leads and increase conversions.